The present invention relates to effecting fluid retention in a fluid-containing food which is heated for consumption.
As is appreciated in the food art, fluid loss and texture deterioration occur in foods, such as vegetables and meat, when treated with heat. Fluid loss and texture deterioration are particularly problematical in the context of so-called convenience foods which are cooked at least partially and then stored in a refrigerated or frozen condition for sale. Because of the steps necessary for preparing a convenience food, fluid loss results in the food acquiring a dry, fibrous and tough texture, which makes the food less desirable than fresh foods to a discerning consumer.
Fluid losses incurred when cooking meat may range, for example, up to from about 15% to about 30% by weight based upon the weight of the meat prior to cooking. Additionally, freezing procedures, and particularly blast freezing procedures, as are known in the art, may contribute to further fluid loss and texture deterioration. Moreover, fluid losses may occur during storage, and further losses also will occur upon heating a pre-cooked meat for consumption.
Particularly problematical are composite food products wherein a meat, in particular, is at least partially cooked and combined with a sauce and then stored for sale in a non-refrigerated, refrigerated, or frozen condition. In this context, although the art has focused, in general, upon inhibiting moisture transfer between food components generally having significantly differing moisture contents to prevent the less moist component from becoming soggy, as in the case of a sauce and a pizza dough, for example, the problem which arises when a meat, such as meatballs, is combined with a sauce is different. That is, even though the meat could be considered the lesser moist component when contained in a sauce, the meat nevertheless contains a substantial amount of fluid, and a portion of that fluid migrates out of the meat into the sauce and thereby dilutes the sauce. Thus, the fluid impairs the viscosity and character of the sauce, and the meat, even though contained in a fluid sauce, acquires a dry, fibrous, tough character. In addition, the problem becomes even more acute when a meat-in-sauce product is retorted, as is common in the art.
Additionally, of particular recent interest in convenience food preparation is a method known as sous vide. An objective of the sous vide process is to provide a convenience product having the aesthetic and organoleptic appeal of a fresh product, and the process is employed desirably for preparing a fish convenience food. In this process, a meat is placed in a pouch, which preferably is transparent, and the pouch is vacuum-sealed. The pouch containing the meat is heated, generally in a water bath, at a temperature of from about 60.degree. C. to about 75.degree. C. until the meat reaches an internal core temperature ("ICT") at least sufficient so that the meat will be microbiologically stable during storage, i.e., generally 60.degree. C. and above. The meat then is held at the stated temperature for about 15 mins to about 20 mins to achieve the required stability. The pouch and contents then generally are chilled to a refrigeration temperature, i.e., generally from about 4.degree. C. to about 8.degree. C., and/or frozen. Advantageously, the consumer needs only to heat the food to a temperature desirable for consumption.
In addition, it often is preferred to impart color to the surface of a meat prior to sous vide preparation or also, for example, for preparation of boil-in-bag products, as are also known in the art, such as by a brief searing, grilling, or frying procedure, to effect a desirable aesthetic effect. That, however, generally also results in a fluid loss which may range, depending upon the character of the meat, up to about 10% by weight which, as is evident from the above discussion, also contributes to a final product having a dry, fibrous, and tough texture.
Furthermore, since fluid separates from the meat during any preparative heating processes, exuded fluids are retained in the package containing pre-heated sous vide and boil-in-bag type products, and during storage, a further amount of fluid, generally from about 5% to about 15% by weight, will be exuded from the meat. Thus, not only does the meat acquire a dry, fibrous and tough textural character, but the exuded fluids also present an unappealing appearance in the package. Even if an absorbent material is included in the package to soak up exuded fluid, the appearance of such is not generally considered appealing either, and these problems are particularly acute when the meat is fish.
As the art reflects, various compositions and means have been proposed to protect foods from effects of atmospheric oxygen and moisture, and/or to "extend" and/or to improve texture and/or to improve fluid retention in foods and/or, as noted above, to inhibit moisture migration between components of composite foods.
One means employed to attempt to obtain a final sous vide meat product containing sufficient fluids, and hence moistness, has been to marinate the meat prior to vacuum-packing it, an illustrative marination medium being exemplified by Savage, et al., U.S. Pat. No. 3,506,455, wherein an aqueous medium containing starch and protein was proposed. However, on one hand, the marination tends to impart a texture to the meat which is not characteristic of fresh meat, and on the other hand, because the marination fluids tend to separate from the solids components of the marinate, the solids tend to form into a granular-type consistency during heating, storage and preparation for consumption.
Various proposals for coating foods also are presented in the art, as reflected in PCT Patent Application, International Publication No. WO 86/00501, in which the invention was directed to preparation of distinct and discrete dehydrated single- or multi-ply films based upon lipid, cellulose-ether-carbohydrate polymer and water ingredients, although it is said that a combination of a lipid and of a starch or a protein polymer, such as albumen, could be employed. After preparation, the film is placed between components of a multi-component food product for inhibiting moisture transfer between the components.
As may be gathered from the PCT Application, coating compositions relying upon the properties of lipids, particularly edible oils, long have been used. Further illustrative of this approach are Verhoef, et al., U.S. Pat. No. 4,935,251, Durst, U.S. Pat. No. 3,323,922, and Bauer, et al., U.S. Pat. No. 3,406,081, which disclose oil-and-water emulsion compositions which contain a film-forming material, which may include a protein such as albumen.
More recently, however, the use of oils has sought to be reduced and desirably substantially avoided, not only because of health concerns but, particularly, to address a lack of effectiveness of edible oil and oil-containing coatings when the coated products are heated. To address those and other problems, U.S. Pat. No. 5,248,512, discloses coating a food with a composition which was found to be particularly useful for preventing moisture migration between two food materials of a composite food product having differing moisture contents. As disclosed, egg, milk protein and water are mixed, and the aqueous composition is coated upon a food and then heated to a temperature of from 70.degree. C. to 100.degree. C., which is disclosed to be critical, to coagulate the egg. The food upon which the composition is coated is usefully the less moist component of the composite food product. As also disclosed, the composition advantageously may include a gelatinized starch, which is disclosed as providing for improving bonding and adhesion of the egg and milk protein to the food.
In addition, aqueous flour-based batter coatings, such as illustrated in UK Patent Application No. 2 097 646, have been proposed, but if one does not desire a browned, breaded product appearance, such flour-based coatings are not acceptable.
A coating mixture of micro-milled salt and carrageenan also has been proposed in European Patent Application Publication No. 0 547 783.
Certain food ingredients also have been employed as meat "extenders". To prepare a "luncheon" meat product, Lindl, et al., U.S. Pat. No. 4,071,635, disclose blending starch, which preferably is gelatinized, and protein components together with water into a mass of comminuted meat to "extend" the meat. After blending, the meat mixture is molded and then cooked. It is disclosed that the starch component acts not only as a filler-extender, but that it is a fat and water binder which acts within the product mass to inhibit escape of fluids from the mass and thereby reduce cooking loss. The protein is disclosed as fulfilling a texture function which improves chew-ability, which is said to be affected adversely by the starch.
Notwithstanding the various approaches noted above, objectives in the art of preparing convenience-cooked meats which have a fresh appearance and character and improved fluid retention, including sous vide and boil-in-bag products, and of preparing meat-in-sauce products, which do not have impaired sauce viscosity, have not been heretofore realized, other than by a process disclosed in European Patent Application Publication No. 0 576 726. As there disclosed, a food product is coated with an aqueous suspension of an ungelatinized starch, milk protein and egg albumen and then the coated product is treated with heat to gelatinize the starch, denature the protein and coagulate the egg. Efficient operation in accordance with that invention, however, involves, generally, concurrent preparation of the aqueous coating composition with the coating operation since, if stored, the aqueous coating should be stored under refrigeration and with stirring to prevent settling of the components, since settling of the components may make reformulating a uniform suspension problematical. Thus, it has been sought to find a coating system and composition which would facilitate material handling and preparation and which would provide results which are at least equivalent with those achieved with the system of the European '726 Application.